[elasticsearch] Return not found instead of error

This commit modifies the Elasticsearch client to return Status.NOT_FOUND
when an operation fails because the document requested does not
exist. This modifies the previous behavior which would return
Status.ERROR in this case.

This commit also moves the statements that would return Status.ERROR
into the corresponding catch blocks so that it is clear that
Status.ERROR is only being returned on error paths.

elasticsearch/src/main/java/com/yahoo/ycsb/db/ElasticsearchClient.java

@@ -30,6 +30,7 @@ import com.yahoo.ycsb.StringByteIterator;
 
 import org.elasticsearch.action.admin.cluster.health.ClusterHealthRequest;
 import org.elasticsearch.action.admin.indices.create.CreateIndexRequest;
+import org.elasticsearch.action.delete.DeleteResponse;
 import org.elasticsearch.action.get.GetResponse;
 import org.elasticsearch.action.search.SearchResponse;
 import org.elasticsearch.client.Client;
@@ -185,8 +186,7 @@ public class ElasticsearchClient extends DB {
    *         description for a discussion of error codes.
    */
   @Override
-  public Status insert(String table, String key,
-      HashMap<String, ByteIterator> values) {
+  public Status insert(String table, String key, HashMap<String, ByteIterator> values) {
     try {
       final XContentBuilder doc = jsonBuilder().startObject();
 
@@ -201,8 +201,8 @@ public class ElasticsearchClient extends DB {
       return Status.OK;
     } catch (Exception e) {
       e.printStackTrace();
+      return Status.ERROR;
     }
-    return Status.ERROR;
   }
 
   /**
@@ -218,12 +218,16 @@ public class ElasticsearchClient extends DB {
   @Override
   public Status delete(String table, String key) {
     try {
-      client.prepareDelete(indexKey, table, key).execute().actionGet();
-      return Status.OK;
+      DeleteResponse response = client.prepareDelete(indexKey, table, key).execute().actionGet();
+      if (response.isFound()) {
+        return Status.OK;
+      } else {
+        return Status.NOT_FOUND;
+      }
     } catch (Exception e) {
       e.printStackTrace();
+      return Status.ERROR;
     }
-    return Status.ERROR;
   }
 
   /**
@@ -241,8 +245,7 @@ public class ElasticsearchClient extends DB {
    * @return Zero on success, a non-zero error code on error or "not found".
    */
   @Override
-  public Status read(String table, String key, Set<String> fields,
-      HashMap<String, ByteIterator> result) {
+  public Status read(String table, String key, Set<String> fields, HashMap<String, ByteIterator> result) {
     try {
       final GetResponse response = client.prepareGet(indexKey, table, key).execute().actionGet();
 
@@ -259,11 +262,13 @@ public class ElasticsearchClient extends DB {
           }
         }
         return Status.OK;
+      } else {
+        return Status.NOT_FOUND;
       }
     } catch (Exception e) {
       e.printStackTrace();
+      return Status.ERROR;
     }
-    return Status.ERROR;
   }
 
   /**
@@ -281,8 +286,7 @@ public class ElasticsearchClient extends DB {
    *         description for a discussion of error codes.
    */
   @Override
-  public Status update(String table, String key,
-      HashMap<String, ByteIterator> values) {
+  public Status update(String table, String key, HashMap<String, ByteIterator> values) {
     try {
       final GetResponse response = client.prepareGet(indexKey, table, key).execute().actionGet();
 
@@ -294,12 +298,13 @@ public class ElasticsearchClient extends DB {
         client.prepareIndex(indexKey, table, key).setSource(response.getSource()).execute().actionGet();
 
         return Status.OK;
+      } else {
+        return Status.NOT_FOUND;
       }
-
     } catch (Exception e) {
       e.printStackTrace();
+      return Status.ERROR;
     }
-    return Status.ERROR;
   }
 
   /**
@@ -321,8 +326,12 @@ public class ElasticsearchClient extends DB {
    *         description for a discussion of error codes.
    */
   @Override
-  public Status scan(String table, String startkey, int recordcount,
-      Set<String> fields, Vector<HashMap<String, ByteIterator>> result) {
+  public Status scan(
+          String table,
+          String startkey,
+          int recordcount,
+          Set<String> fields,
+          Vector<HashMap<String, ByteIterator>> result) {
     try {
       final RangeQueryBuilder rangeQuery = rangeQuery("_id").gte(startkey);
       final SearchResponse response = client.prepareSearch(indexKey)
@@ -336,18 +345,16 @@ public class ElasticsearchClient extends DB {
 
       for (SearchHit hit : response.getHits()) {
         entry = new HashMap<>(fields.size());
-
         for (String field : fields) {
           entry.put(field, new StringByteIterator((String) hit.getSource().get(field)));
         }
-
         result.add(entry);
       }
 
       return Status.OK;
     } catch (Exception e) {
       e.printStackTrace();
+      return Status.ERROR;
     }
-    return Status.ERROR;
   }
 }